Manufacture of phosphorus oxychloride and thionyl chloride



CHLORIDE April 8, 1930. G. J. scHuDEL MANUFACTURE OF PHOSPHORUS OXYCHLORIDE AND TH'IONYL Filed Nov. 18. 1926 col-42101.3 lphuric d l i mixing zmf %M f I INVENTOR.

I .ATTORNEY$ GEEK- ii J. SGHUDFJIJ, OF :urrno, WEST VIRGENIA, ASSIGEI I'OR, BY ASSIGNMENTEZ, I

T0 ELKO QHEMICAL COMPANY, A-CDEPORATIUN 6F WEST VIRGINIA .LLMTUEACTUEE OF PHOSBHORU 0X1? CHLORIDE AND TEIGNYL @HLQRIDE Application filed November 3.8; 1926. serial No. mecca,

My invention relates particularly to a process of making phosphorus oxychloride and thionyl chloride, and has relation especially to the manufacture thereof with the aid of chlorine and sulphur dioxide.

Both phosphorus 'oxychloride and thionyl chloride are becoming of increased import-- ance as the demand for and use of the same is steadily increasing.v For example, phos phorus o'xychloride is being used extensively "as a condensing agent in a large number of for example, the oxidation of phosphorus trichloride with potassium chlorate (dour. pr; Chemie, 1883, (2) vol. 23, p. 283) the reaction between pentachloride and water 7 (G. @ddo, G. 25, H, p. 380) by passing chlorine over heated calcium metaphosphate and s coal {German Patent 138,392) the reaction of phosgene upon calcium phosphate (U. S. Patent 1,424,193); by passing sulphur dioxide gas over phosphorus pentachloride {Annalen 102; 111, 1857); the reaction of sulphuryl chloride with phosphorus trichloride (German Patent 415,312). Also it has been proposed to make thionyl chloride bv the action of sulphur dioxide gas on phosphorus pentachloride (Sohifi, Annalen, 102, page ill, 1857), which, however, gives only 50% oi the theoretical quantity (Vanino,

' Praen. @hemie, 1', p. 94) g or action of sulphuryl chloride on phosphorus trichloride (German l atent 415,312) the interactionpi sulphur 'trionide, sulphur chloride and chlo-' rine (German Patent 139,455) g the reaction between sulphuryl chloride and-cartoon monoxide, 'ohosgene sulphur dioxide (Gert Que- ,935},

hese previous processes for prothese compounds are, however, ed and expensive. example, o as pentachloride is expensiye and its on with sulphur dioxide is slow and furthermore, a poor yield,- The obtained it our phosphorus trichlo separate in view of the boiling points, the boiling point of sulphuryl' chloride being- 68-69" (1, phosphorus trichloride 74 (3., thionyl chloride 7 879 {(1, and phosphorus oxychloride 107 C.

I have found that when chlorine and sulphur dioxide are mixed together, as hereinafterreferred to in carrying out. the desired reaction, and used simultaneously either as a mixture of gases or as liquefied gases, that this mixture reacts with phosphorus in its elemental form (either red or yellow) or with phosphorus trichloride according to the following reactions:

These reactions are instantaneous and quantitative and avoid the disadvantages'of other processes. The result could not have been foreseen as it would have been expected that all of the phosphorus would react first to form phosphorus trichloride and then phosphorus pentachloride before any reaction would take place with sulphur dioxide. in carrying out my invention 1 have found that the phosphorus or phosphorus trichloride could bepresent in any desired excess when using sulphur dioxide and chlorine in the proper'ratio, the only products obtained be ing phosphorus oxychloride and thionyl chloride, The rate of the reaction is controlled by the amount or" external cooling applied, and the reaction may be carried out in an open container unless it is conducted at a temperatui e above-the hoiling point of thionyl chloride, in which case a reflux condenser may be attached, or the'thionyl chloride may be distilled off as formed.

My prior application upon Liquefied gases and process of using same, executed on the 29th day of Septemher, 1926., is related generically to the present invention, and is Serial l lo, 140,427, filed @ctober 8, i926 VThile my invention is capable of embodiment in many different forms, it have described only certain forms of the same in de-' tail herein, and while it is capable of being carried out in many d rent types oi apparatus, l'have shown only one type of arena- Mill where'a reflux condenser is to be used. It

will be understood, however, that, if desired,

the reflux condenser may be omitted, as above pointed out. I

For example, in carrying out my invention I may introduce 32 pounds of liquid sulphur dioxide into a closed pressure vessel 1 by means of a pipe 1*, and thereafter I may introduce 88.7 5 pounds of liquid chlorine into the same. An outlet pipe 2 is provided from thevessel 1, which discharges into a still 3 below the surface of the liquid therein. .The'

still'3 may have a cooling jacket 3 provided with a current of cooling water bymeans of inlet and outlet pipes 3 and 3. Said still 3 also has a charging hole 3 and a valved drain pipe 3, as well as a thermometer 3. The

' liquid in the still 3 is preferably comprised of a liquid carrier such asa solvent or diluent for the phosphorus, such as phosphorus oxychloride or thionyl chloride, or a mixture of both, in order to avoid the introduction of other undesirable compounds. However, a diluent such as carbon tetrachloride, may be used, if desired. For example, I may use16.5 pounds of red or yellow phosphorus suspended or melted respectively under sufiicient of the, liquid as, for instance, phosphorus oxychloride, to protect the phosphorus from any air that might be present, that is to say, about 25 pounds of phosphorus oxychloride or more. Or, instead of phosphorus oxychloride the mixture of thionyl chloride and phosphorus oxychloride resulting-from a previous operation may be used, that'is to say, 25 pounds of the mixture or more. If desired, the liquid sulphur dioxide andchlorine may be allowed to expand prior to entering the still 3 before thereactiombut preferably the mixed liquids which form a solution are introduced directly into the contents'of the still-3 in order to utilize the cooling effect of the same. As a resuit a lively reaction ensues, which is controlled by adjusting the amount of mixed liquid gases fed into the same and the amount of external cooling applied. The endof the reaction may beobserved by one or more of temperature a change in color of the reaction mixture; and by" cessation of the complete absorp'tion of the mixed gases or liquids. In case the above reaction isconducted at a temperature above the boiling point of" into a trap 8 containing sulphuric acid and meavca having a vent-pipe 9. After the reaction product has, thus, been obtained the components of the reaction mixture may be separated byfractional distillation in an efiicient column.

It will be understood that many changes may be made "in the proportions of the materials above used, as well as the order in which they are introduced, and the temperatures under which the reactions are cone ducted, etc. For example, the phosphorus may be wholly or partly replaced by phosphorus trichloride, and the ratio of sulphur dioxide and chlorine changed accordingly.

While I have described my invention above in detail I wish it to be understood that many changes may be made therein without departing from-,the-s'pirit of the same.

I claim: f

1. The process which comprises producing phosphorus oxychloride and thionyl chloride by the reaction of sulphur dioxide and chlorine on phosphorus.

2. The process which comprises producing phosphorus oxychloride and thionyl chloride by the reaction of a mixture of sulphur dioxide and chlorine on phosphorus thesul- 'phur dioxide and chlorine being in the form of a liquid.

3. The process which comprises producing phosphorus oxychloride and thionyl chloride by the reaction of a mixture of sulphur dioxide and chlorine on phosphorus contained in a liquid carrier.

The process which comprises producing phosphorus oxychloride and thionyl chloride by the reaction of a mixture of sulphur dioxide and chlorine on phosphorus contained in a liquid carrier, the sulphur dioxide and chlorine being in the form of a liquid.

-5. The process which comprises producing phosphorus. oxychloride and thionyl chloride by the reaction of a mixture of sulphur dioxide and chlorine on phosphorus I contained in a liquid carrier, said liquid car- 6. The process which comprises producing phosphorus oxychloride and thionyl chloride by the reaction of a mixture of sulphur dioxide and chlorine on phosphorus conide and chlorine being in the form of a liquid, said liquid carrier being a compound such as formedin the above reaction.

- 7. The process which comprises producing phosphorus oxychloride by the reaction of a mixture of sulphur dioxide and chlorine on phosphorus, the sulphur dioxide and chlorine being inthe form of a liquid.

..t"d" l"d 'th 1h"- the following conditions? a distinct fall in ame m a lqm earner e p ur dlox 8. The process which comprises producing phosphorus oxychloride by the reaction of a mixture of sulphur dioxide and chlorine on phosphorus contained in a liquid carrier, said liquid carrier being a.- compound such as formed in the above reaction.-

9. The process'which comprises producing phosphorus oxychloride by the reaction of a mixture of sulphur dioxide and chlorine on phosphorus contained in a. liquid carrier, the

sulphur dioxide andchlorine being in the, form ofa liquid, said liquid carrier being a compound such as formedin the above reaction.

10. The

process which comprises producing thionylchloride by the reaction of sul- I phur dioxide and chlorine on phosphorus.

. 11. The process which comprises producing. thionyl chloride by the reaction of a mixture of sulphur dioxide and chlorine on phosphorus, the sulphur dioxide and chlorine being in the form of a liquid.

.12. The process which comprises produc ing thionyl chloride bythereaction of 'a mixture ofsulphur dioxide sndchlorine phorus contained in ailiqu'id carrier.

13. The process which comprises roducing thionyl chloride bythe reaction 0 a mixture of sulphur dioxideand chlorineon phosphorus contained in a, liquidcarrier, the sulv phur dioxide and chlorine being in the'form' ofaliquid;

'14. The process which comprises reducing thionyl chloride by ture of sulphur dioxide and chlorine on phosphorus contained in a liquid carrier, uidicarrier being a compound such as formed inthe'abovereaction; f

'15." ingthionyl chloridebythe reaction 0 a, mix- ;tureof sulphur dioxide andchlcrineon phosphorus'contained inva. liquid carrier; the sulphur dioxideand chlorine beingin the form of'a. liquid, said liquid carrier being a com-; pound such as formedimthe eboveireaction that I claim-theforegoing, 1-

my hand this 30th dayof In testimony have hereuntoiset October, 1926; a e

i 'GEQRGE- .Jj,- SCHUDEL. I

the reaction 0 a mix said liq- I The process'whichf'fcornprises roduc 

